Portable air compressor



Jan. 19, 1932. T. G. JONN 1,842,027

7 PORTABLE AIR COMPRESSOR Filed Aug. 6, 1950 s Sheets-Sheet 1 50 UVELF'ZZUI" =7aye 63/0731 4 Jan. 19, 1932. T, JONN 1,842,027

IORTABLE AIR COMPRESSOR Filed Aug. 6, 1930 3 Sheets-Sheet 2 Jan. 19, 1932. T. G. JONN PORTABLE AIR COMPRESSOR Filed Aug. 6, 1950 5 Sheets-Sheet 3 UVEF SF Jaye 6? L/m'm v the compressor unit is operated Patented Jan. 19, 1932 FFECE- G. J ONN, OF CHICAGO, ILLINOIS, ASSIGNOR TO BREUER ELECTRIC MFG. 00., OF

CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS PORTABLE AIR COMPRESSOR Application filed August a, 1930. Serial No. 473,463.

This invention relates to a portable air compressor, and particularly to an elec trically driven compressor wherein reduction gearing or similar means is eliminated between the motor unit and the compressor unit and wherein the compressor is actuated atthe full normal speed of the motor with out overloading the motor and without impairing the efliciency of either the motor or the ,';compressor.

There are in use at the present time portable air compressor units electrically driven, but all of these employ reduction gearing or similar speed-reducing means between the motor and the compressor, resulting in an expensive construction and increasing the liability for damage and the likelihood of being easily broken or rendered ineffective fo efiicient use. I I

The present invention seeks to provide a portable air compressor having an electric motor directly connected to the compressor unit, so that the compressor unit is operated at the full normal speed of the motor without reduction gearing or equivalent means interposed between the motor and com pressor.

An object of the present invention is to provide a portableair compressor wherein at full maXimum speed of the motor. i p

'Another object of the invention is to provide a portable air compressor with a double piston directly connected to the electric motor shaft.

A further object of the invention is'to provide an air compressor for supplying two compression strokes per revolution of motor shaft. V

A still further object of the invention is to provide a portable compressor unit electrically driven, wherein a heavy flywheel is secured on themotor shaft and directly conpiston.

' A still further object of the invention is to provide a portable air compressor having double ported heads for the compression cylinders wherein very light, readily movable cruciform disc valves are utilized for controlling passage through the ports,

Another and still further object of the invention is to provide a portable air compressor having double opposed pistons effectively driven by a single crank associated with one of the pistons.

An additional object of the invention is to provide an air compressor having a strainer and water collector interposed between the compressor and the storage tank.

Another and yet further object of the invention is to provide a portable air compressor including an electric motor, a compressor and a compressed air storage tank grouped together on a common base and provided with a handle for easy portability.

Generally speaking, the invention contemplates an electric motor and compressor unit mounted on a single base, together with a compressed air storage tank, the compressor including double opposed compression cylinders with a piston in each cylinder, the pistons being connected for simultaneous operation, a flywheelon the motor shaft which flywheel is provided with a crank pin operatively associated with a pitman which is pinned to one of the pistons. The invention further contemplates the provision of heads for the compression cylinders, each head hav-' ing an inlet port and outlet port, which ports are controlled by thin cruciform discs operating as valves for controlling passage through the ports.

The above, other and further objects of the invention will be apparent from the following description, accompanying drawings and appended claims.

An embodiment of the present invention is illustrated in the accompanying drawings, and the views thereof are as follows:

Figure 1 is a side elevational view of a portable air compressor embodying the present invention, showing the manner in which the various units are assembled for ready portability.

Figure 2 is an enlarged vertical sectional view through one of the heads for the compression cylinder.

Figure 3 is an enlarged vertical sectional view taken substantially in the plane of line IIIIII of Figure 1.

Figure 4 is an enlarged vertical sectional view of a fragmental portion of the cylinder head showing certain details of construction of the valve structure for a port.

Figure 5 is a vertical sectional view through the compressor unit, with a fragmental portion of the storage tank and the flywheel and hub in section, showing the relation of the flywheel to the pitman and the piston, and a strainer interposed between the compressor and the storage tank.

Figure 6 is a section on line VIVI of Figure 1-.

A base plate A is supported on feet B. The motor C is provided with feet 1 which are secured to the base plate A by bolts 2. The compressor E is attached to the base plate A by bolts 3 passing through a flange 4 formed with the compressor casing. The storage tank D is supported above the motor C by long bolts 5 which, at the lower end, pass through the plate A and are maintained in position by nuts 6, with the upper ends of the bolts engaging a strap 7 underlying the tank D and supported on the bolts 5 by nuts 8, with a handle casting 9 bearing against a portion of the upper surface of the tank D and having ears 10 which are apcrtured to receive the upper ends of the bolts 5 and held in position on the bolts by nuts 11.

The storage tank D is provided with a valve 12 which may be connected to a hose 13 or other suitable conduit whereby the compressed air within the tank D may be utilized.

The compressor E is formed with two double opposed cylinders 14 and 15 which are illustrated as horizontal. The cylinders are formed in the compressor casting. The outer end of each of the cylinders 14 and 15 is closed by a head F, leaving the contiguous ends of the cylinders open.

A. piston 16 is reciprocable within the cylinder 14, while a similar piston 17 is reciprocable within the cylinder 15. Each of the pistons is disposed with its head toward the respective head of the cylinder and with the other ends of the pistons open in the usual manner. Each piston is provided with piston rings 18 for sealing the cylinders against escape of compressed air past the pistons.

The two pistons 16 and 17 are connected by a rib 19 laterally disposed of the axis of the pistons for the purpose of avoiding the crank mechanism to be later described.

The motor C is provided with a motor shaft 20 which carries a heavy flywheel 21. The hub 22 of the flywheel is elongated and provided with a centrally disposed aperture 23 for receiving the end of the motor shaft 20. The hub is fastened to the motor shaft by means of a setscrew 24 or equivalent means. The outer end of the hub 22 is provided with a crank pin 25 which is eccentric with respect to the axis of the motor shaft 20.

One of the pistons, such, for instance, as piston 17, is provided with the usual wrist pin 26 which carries a pitman 27 the other end of which engages over the crank pin 25 on the flywheel hub 22. The pitman is provided with a downwardly extending leg 28 for entering an oil compartment 29 for the purpose of splashing oil upwardly into the cylinders as the pistons are reciprocated for the purpose of lubrication.

The compressor casing is provided with a chamber 30 which communicates with the head F for receiving compressed air from the cylinders. The casing is provided with a threaded aperture 31 into which is threaded the end of a delivery pipe 32. A strainer casting 33 is threaded onto the threaded end of the delivery pipe 32 surrounding said pipe and with the walls thereof spaced with respect to said pipe. The upper end of the delivery pipe 32 is provided with a closed top and alateral opening 34 through which the compressed air is discharged into the strainer casing 33. The strainer 33 is provided with a threaded aperture 35 in one of its sides for receiving a threaded nipple 36 communicating with the tank D for delivery to the tank of the compressed air delivered to the strainer casing 33. A bafiie plate 37 is cast integrally with the casing 33 and extends outwardly from below the opening 35 and then upwardly in front of said opening so as to prevent direct communication between the outlet 34: of the delivery pipe 32 and the entrance to the storage tank D for compressed air.

The upper end of the storage casing 33 is normally closed by a threaded plug 38 which is provided with a polygonal recess 39 for receiving a tool, for insertion or removal of the plug. The lower end of the strainer casing is provided with a drain outlet which is normally closed by a threaded plug 40.

A pressure gauge G is provided communicating with the compartment 30 of the com.- pressor casting. A safety valve H communicates with the chamber 30 and may be adjusted to relieve excessive pressure within the chamber 30 in the event excessive pressure is therein created. The safety valve H may be of any usual and suitable form.

Each of the heads F is made preferably as a casting with a cylindrical body 4.1 for fitting into the outer ends of the cylinders 14: and 15 and closing the cylinders at these ends.- The body 41 is fitted with a piston ring 42 to prevent escape of compressed air from the compartment 30 into the cylinders. The outer end of each of the heads F is pro vided with a double counter bore, the outer, 43, being of greater diameter than the inner one, 44. An annular shoulder 45 is formed at the junction of the counter bores 43 and 44. A screen 46 is placed on the shoulder 45 and held thereagainst by a spring ring 4'? which enters a recess 48 formed in the outer counter bore 43, thus locking the screen 46 in position. Each head F is provided with a'fiange 49 which is provided with a series of bolt holes 50 whereby the head may be secured by means of bolts 51 engaging aper tured lugs 52 on the compressor casting.

Each head is provided with a bore 53 extending inwardly from the counter bore 44 to the inner surface of thehead. The bore 53 is provided with a counter bore 54 for receiving a valve structure.

Another bore 55 is formed in the head F and extends toward the outer end thereof from the inner end, stopping short of the inner counter bore 44. This bore, likewise, is provided with a counter bore 54. A lateral passage 56 extends from the bore 55 and opens outwardly of the body of the head F and is opened through a side of the head. The parts are so arranged that, when a head is inserted in the end of a cylinder, the lat eral outlet or passage 56 will be in communication with the chamber 30 of the compressor casting and outwardly of the outer end of the cylinder portion of the same.

Thevalve structures which are inserted in the counter bores 54 are similar in constructi on but reversed as to position.

The bore. 53 constitutes the inlet and the bore 55 and lateral passage 56 constitute the outlet for each head.

The valve structure includes a cylindrical body 57 having an end 58 in which there is a centrally disposed opening 59. This end of thebody is otherwise closed except for the opening 59. A plate 60 is secured to the other end of the body 57 from the end 58, and this plate, likewise, is provided with a central opening 61 which has a collar 62 as an integral part thereof, which collar extends to ward the other end 58 of the valve structure. The width of the plate 60, however. is less than the diameter of thebody 57 of the valve structure, thus providing spaces on each side of the side margins of the plate and the interior ofthe body 57of the valve structure. These spaces are indicated at 62in Figure 4. The openings 59. and 61 are substantially of the same diameter. The contiguous ends of the collar 62 of the plate 60 and the ends 58 of the-valve structure are spaced, and a disc valve 63 of thin, lightmaterial is interposed in this space. The disc 63 is'cruciform in contour, asclearly'shown in Figure 6, and Wltll the central portion thereof of sufficient size to overlie the central openings 59 and 61. V

V Figure 2 illustrates one of the heads F with two of the described valve structures incorporated therein. These structures are similar in every respect except reversed as to position. i

'The end 58 of the valve structure is provided with a rabbet 64. The rabbet 64 cooperates with the shoulder formed between the counter bore 54 and the bore 53 of the inlet.

The valve structures just described are retained in position in a head F by means of a circular plate 65 which plate is provided with an aperture 66 for registering with the port 61 in the valve structure in the inlet and an aperture 67 engaging the rabbet 64' of the end 58 of the valve structure in the outlet. The plate 65 is retained in position by means of flat headed machine screws 68 which engage suitable openings in'the plate and which pass through apertures in the body of the head F, being secured in position by nuts 69.

It will be observed that a head F for one of the compressor cylinders is a self-contained unit and carries the inlet and outlet ports, as well as the valve structures for controlling passage through these ports. Such head also carries a strainer for cleaning incoming air. The cruciform valve disc 63, by reason of the provision of the cut-out portions in its margin to form the cruciform, allows air passage thereby under certain conditions.

The disc 63, being very light, is immediately responsive to pressure changes in the com pressor when the same is operating.

The provision of the heavy flywheel 21 stores up energy as the motor is operating and dissipates this energy in actuation of the piston for compressing air, thus making possible the operation of the compressor at high speed, which is the speed of the motor.

The piston rings 42 are inserted in suitable grooves in the heads F in white lead so as to effectively seal the working ends of the cylinders against escape of compressed air in either direction.

An apparatus embodying the present in vention has beenofound to develop forty or more pounds pressure when the connection 12 of the storage tank was open, that is, when the air compressor was working in connection with a suitable tool, such as a paint sprayer or like instrumentality.

The compressor is readily portable and may be utilized where an ordinary portable compressor would be inadequate to furnish the proper working pressure required. The provision of the double compression cylinders enables two compression strokes per revolution of the motor, thus increasing the efficiency of the aparatus.

The operation of the illustrated form of the invention is as follows: N

Ian

The motor C is, of course, connected by any suitable conductor to a source of electricity and, when started, rotates at normal speed, which, with a A H. P. motor, is approximately 1700 R. P. M.

The moment the motor starts rotating, the flywheel 21 rotates, storing up energy as the motor reaches its maximum speed. The pistons 16 and 17 are reciprocated through the pitman 27 as the crank pin on the flywheel hub 22 rotates with the flywheel and motor shaft. Thus, it will be observed there are two working strokes per revolution of the motor.

On the suction stroke of either cylinder, air is drawn in through the inlet 53, with the valve disc. 63 against the collar 62 in the lower valve structure, as illustrated in Figure 2, the air passing through the cut-out portions of the valve disc through the passages 62 each side of the plate 60, thence through the opening 66 in the plate into the cylinder 14. The movement of the piston 16 to the right on the suction stroke creates suction whereby the valve disc 63 of the outlet is held against the opening 59 in the valve structure, thus sealing this opening against communication with the chamber 30, the central imperforate portion of the valve disc 63 overlying the opening 59 of the valve structure during this movement of the piston 16 to the right under suction, permitting passage to the cylinder through the opening 59, as there are, in the valve structure as arranged in the bore 55, no side passages communicating with the aperture 59.

The moment the piston 16 reaches the end of its suction stroke, that is, the stroke to the right as viewed in Figure 3, the piston starts to the left. Immediately such movement moves the lower valve disc 63 to the left as viewed in Figures 2 and 3, thus closing the inlet opening and sealing it against escape of air. The valve disc 63 in the outlet is moved against the collar 62 of the plate 60, and, by reason of the spacing of the side margins of the plate 60, allows passage of air from the cylinder 14 through the opening 59 of the outlet valve structure about the disc (53 through the spacer 62, thence into the bore 55, thence laterally through the passage 56 into the chamber 30, where the air passes upwardly through the strainer 33 and thence into the storage tank D. The operation of 3 the head F in the cylinder 15 is exactly the same as that just described, but reversed as to operation, that is to say, when the pistons are moving to the right, the cylinder 15 is in compression and cylinder 14 in suction, and, when the pistons are moving to the left, the reverse prevails.

Provision of the strainer 46 prevents entrance of foreign matter to the compression cylinders.

It will be observed that the provision of the head F makes readily accessible the interiors of the cylinders, the valve structures and related parts for easy maintenance and upkeep.

The sump 26 is filled with oil which is splashed by the extension 28 of the crank 27 against the piston and transferred to the cylinder walls, thus eflectively lubricating the cylinders.

The gauge G indicates at any time the pressure of air within the compartment 30, and, should the pressure exceed any predetermined amount, the safety valve H functions to allow escape of the excess pressure to the atmosphere.

The valve structures are highly efficient in use, sturdy and strong and capable of continued use for long periods of time.

An air compressor embodying the present invention has been found to work very satisfactorily and, as before stated, creates a working pressure of forty pounds plus when the connection 12 of the storage tank is open.

The parts are so designed, arranged and assembled as to reduce the cost of manufacturing the various parts and assembling the same and also maintaining the apparatus in a high state of efficient use.

The invention has been described herein more or less precisely as to details, yet it is to be understood that the invention is not to be limited thereby, as changes may be made in arrangement and proportion of parts and equivalents may be substituted without dcparting from the spirit and scope of the in vention.

The invention is claimed as follows:

1. An air compressor including in combination, a storage tank, a chamber between said compressor and said tank, a restricted inlet into said chamber from said compressor, an outlet from said chamber to said tank, and a bafile adjacent said outlet to prevent direct communication between said inlet and said outlet within said chamber.

2. An air compressor including in combination, a storage tank, an air compressor, a chamber between the compressor and the tank, a restricted inlet into said chamber near the bottom thereof leading from said compressor, an outlet from said chamber to said tank, said outlet being above said inlet, a baflie adjacent said outlet to prevent direct communication between said inlet and outlet, and said chamber having a drain in its lower end.

3. A cylinder head for air compressors including a member insertable in a compressor cylinder, said member having a counter bore in its outer end, said member also having a bore extending through said member from said counter bore to the inner end of the member, another bore extending inwardly from the inner end of said member and stopping short of the counter bore, said memher having a lateral passage leading from said last-mentioned bore and opening in the side of said member, said first bore constituting the inlet and said second bore constituting the outlet, a valve structure in each of said bores, and disc valves in said valve structure for opening and closing said bores to passage of air through the same. 7

In testimony whereof I have hereunto subscribed my name at Chicago, Cook County,

Illinois.

TAGE G. J ONN. 

